European Journal of Biomedical and Pharmaceutical Sciences

SYNTHESIS AND SPECTRAL CHARACTERISATION OF IMIDAZO [1,2A] PYRAZINE DERIVATIVES

M. Tulasi Devi and Chava Venkata N. Rao*

ABSTRACT

New pyrazine derivatives are synthesized in this work. 5-methyl 2-amino pyrazine reacted with 3-methyl 4-chloro phenyl acyl chloride to obtain 2- (4’-chloro 3’ – methy1 pheny1) 6-methy1 imidazo [1,2a] pyrazine (1) which on reacting with NBS yielded 3-bromo 2- (4’-chloro 3’ – methy1 pheny1) 6- methy1 imidazo [1,2 a] pyrazine (2). Compound 1 reacts with sodium acetate and formaldehyde in presence of AcOH gave (2 – (4’ chloro 3’ – methy1 phenyl) 6- methyl imidazo [1, 2 a] pyrazine – 3 – yl) methanol (3).This compound reacts with PBr3 to produce 3-bromomethyl – 2-(4-chloro-3’ methyl phenyl) 6-methyl imidazo [1, 2a] pyrazine (4). The same compound 3 reacts with thiophenol to produce 2 – (4’- chloro 3’ – methyl phenyl) 6 – methyl 3 – ((phenylthio) methyl) imidazo [1, 2 a] pyrazine compound (5). 5-methyl 2-amino pyrazine dissolved in ethyl alcohol reacts with t-butyl bromomethyl ketone to produce 2-tert – butyl 6-methyl imidazo [1, 2a] pyrazine compound (6). Compound 6 reacts with NBS to give 2-tert – butyl 3- bromo 6- methyl imidazo [1, 2a] pyrazine compound (7). Compound 6 on reacting with formaldehyde in sodium acetate and acetic acid gave the compound (2 – tert – butyl 6 – methyl imidazo [ 1, 2a] pyrazine -3 –yl) methanol compound (8). The same compound 6 on reacting with thiophenol and acetic acid produced compound 2- tert – butyl 6 – methyl – ((phenylthio) methyl) imidazo [1,2a] pyrazine compound (9). Al these compounds (1-9) structure was confirmed with the help of IR, 1H NMR and Mass spectral data.

Keywords: Pyrazine derivatives, 5-methyl 2-amino pyrazine, 3-methyl 4-chloro phenyl acyl chloride, t-butyl bromomethyl ketone, IR, 1H NMR and Mass spectra.